Field of the Invention
The present invention relates to a semi-closed type refrigerant compressing machine. More particularly, it relates to an improvement in a motor installed in such machine.
For a refrigerant compressing machine used for a cooling apparatus, a refrigerator and so on, a semi-closed type one which hermetically receives a motor and a compressor in a casing has been used to increase air-tight property for a refrigerant gas.
An example of the conventional semi-closed type refrigerant compressing machine is shown in FIGS. 1 and 2. In the Figures, reference numerals 1a and 1b respectively designate the inlet side and the outlet side of a chamber for a motor which comprises a stator 2, a winding 3 wound on the stator 2 and a rotor 4, the stator and the rotor being formed by aluminum die-casting. A reference numeral 5 designates vanes formed in one side surface of the rotor so as to project in the radial direction. For the vanes, gates for forming the rotor by die-casting operation of a molten metallic material are utilized and they are remained without cutting in the finishing operation. The rotor 4 is firmly secured to a shaft 6. The motor and the other structural components are hermetically sorrounded by a casing 7 which is provided with a refrigerant gas intake port 8. In the casing 7, a refrigerant gas passage 9 is formed between the inner surface of the casing 7 and the outer peripheral surface of the stator 2 and an air gap 10 is formed between the stator 2 and the rotor 4.
In the conventional compressing machine having the construction as above-mentioned, when a compressor (not shown) is driven by the shaft 6 as an output shaft of the motor, the refrigerant gas flows into the inlet side la of the chamber for the motor through the intake port 8 and is passed through the passage 9 and the air gap 10 in the motor to be discharged through the outlet side lb for the motor chamber whereby the motor is cooled by the refrigerant gas. In this case, since the refrigerant gas stirred by the vanes formed integrally with the rotor 4, the stator winding 3 neighboring the vanes is cooled. As a result, the temperature of the refrigerant gas increases from the inlet side of the motor chamber to the outlet side thereof and accordingly the temperature of the stator winding indicates the same tendency. Namely, the vanes 5 attached to the rotor 4 do not effectively contribute the cooling of the stator winding and the highest temperature portion of the stator winding tends to be located at the outlet side of the motor chamber.